Wire stripping mechanism



Nov. "l0, 1970 1. R. METCALF 3,538,796

WIRE STRIPPING MECHANISM 3 Sheets-Sheet l Filed April 23. 1968 Nov. 10, 1970 l. R. METCALF 3,538,796

i WIRE STRIPPING MECHANISM Filed April 23. 1968 5 Sheets-Sheet 2 i j /z/ Nov. 1o, 1970 l. R. METCALF 3,538,796

WIRE STRIPPING MECHANISM Filed April 23, 1968 3 Sheets-Sheet 5 United States Patent Oiiice 3,538,796 Patented Nov. 10, 1970 ABSTRACT F THE DISCLOSURE A precision wire stripper having a pair of actuating handles which are moved together in a straight line motion for stripping insulation from a wire. The initial movement of the handles towards each other pivots slug pullers and insulation cutting members to both contact the insulation and to sever a portion of insulation from the wire. Pivotal movement of the slug puller and insulation cutter members is brought about by a rod which remains stationary relative to at least one of the movable handles. Continued movement of the handles towards each other moves the slug puller and insulation cutter members apart to separate the severed portion of the insulation from the remainder of the insulation on the wire. Relative linear movement of the slug pulling and insulation cutter members is accomplished 'by mounting one of the members on the front handle housing and the other member on a shaft extending through this housing. This shaft is free to move relative to the front handle housing except during the initial movement of the handles when a detent holds the shaft. The detent is released when the shaft and front handle housing move a limited distance relative to the second handle housing. A scissors type wire cutter is mounted on the front handle housing, and an actuating rod is mounted on the rear handle housing. The actuator rod has a tapered portion which engages the cutter members to force the scissor type blades together when the handle housings are moved towards each other.

SUMMARY OF THE 'INVENTION This invention is concerned with a precision wire strip.- per having cutter and slug pulling members which pivot into stripping contact with an insulated wire and which are moved apart along a straight line to strip the wire by a continuous straight line movement of actuating handles.

An object of this invention is a wire stripper in which cutting of the insulation and removal thereof f rom the wire is accomplished by a continuous straight line movement of actuating handles.

Another object is a wire stripper in which the elements of the cutting and slug pulling members are pivoted into engagement with the insulation.

Another object is a wire stripper in which the stripped portion of the wire is automatically cut to the proper length during the stripping operation.

Other objects may be found in the following specification, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated more or less diagrammatically in the following drawings wherein:

FIG. l is a side elevational view of a wire stripper embodying the features of this invention;

FIG. 2 is a cross-sectional view of the structure of FIG. 1 with parts broken away;

FIG. 3 is a top plan view of the structure of FIG. 1;

FIG. 4 is a view similar to FIG. 2 but showing the wire stripper in its fully actuated position;

FIG. 5 is an enlarged partial front elevational view of the structure of FIG. 1;

FIG. 6 is an enlarged cross-sectional view taken along line 6-6 of FIG. 4 with parts omitted for clarity;

FIG. 7 is an enlarged cross-sectional view taken along line 7-7 of FIG. l;

FIG. 8 is an enlarged partial view taken along line 8-8 of FIG. 4;

FIG. 9 is an enlarged front elevational view of the wire positioning member; and

FIG. 10 is an enlarged partial side elevational view of the structure of FIG. 9;

FIG. 1l is an enlarged partial view, with parts omitted for clarity, of the cutter and slug puller members in their closed positions.

DESCRIPTION OF THE PREFERRED' EMBODIMENT A stripper embodying the novel features of this invention is shown in FIG. 1 and includes a telescoping housing 11 consisting of a front portion 13 and a rear portion 115. As seen in FIG. 4, the front portion telescopes into the rear portion. Handles 17 and 19 are formed as integral parts respectively of the front and rear portions.

As shown in FIG. 2, a bore 21 extends through the front housing portion 13 and aligns with a bore 23` extending partially through the rear housing portion 15. A bushing 25 (shown in detail in FIG. 8) lits into an enlargement 26 at the front end of the bore 21 and extends outwardly thereof. Set screws 27 secure the bushing to the housing portion 13. A shaft 28 is positioned in the bore 21 and one end thereof extends into the bore 23. The opposite end of the shaft extends outwardly of the bore 21 and beyond the bushing 2-5. The shaft is limited in movement relative tothe rear housing portion 15 by a pin 29 which extends through the shaft and rides in elongated slots 31 formed in the rear housing portion 15.

An insulation cutter assembly 33 is mounted on the outer end of shaft 28. This assembly, as shown enlarged in FIG. 5, includes a pair of cutter carriers 35 having openings 37 formed in hub portions 38 thereof. The openings it around an end portion 39 of the shaft, which is of reduced cross-section, to pivotally mount the cutter carriers on the shaft. Cutters 40 are attached to the carriers in any conventional manner such as by brazing, threaded fasteners or pins. The cutters may also be formed as integral parts of the carrier. The manner of attaching the cutters to the carriers is conventional and forms no part of this invention. Notches 41 of various sizes are formed in the cutters to receive wires of various sizes and these 4are also of conventional construction. The cutters may also be of any other conventional design. The portions 42 of the carriers to which the cutters are attached may be offset laterally relative to the hub portions 38 of the carriers as shown in FIG. 8. This aligns the cutter 40 when the hub portions of the cutter carriers are placed side by side on the shaft.

A torsion spring 43 is connected at its opposite ends to the cutter carriers 35 and extends around the shaft 28 to urge the cutters 40 apart. Spreading of the cutters iS limited by engagement of the end portions 44 of the cutter carriers with a tab to be described later. End portion 44 is located on the opposite side of the hub 38 from the cutter support portion 42. These end portions are offset from the hubs in alignment with the cutter support portions 42. A cover 45 is positioned over the spring 43 and the spring and cutter assembly is held to the shaft 28 by means of `a screw 47. A pin 48 and mating socket 49 are formed in carriers 35 adjacent the tips of the cutter support portions 42 to hold the cutters in position during linear movement thereof.

A slug removal assembly comprising blades and carriers generally similar to the cutter carrier assembly S3 (FIG. 6) is fitted on the bushing 25 connected to the front housing portion 13. This assembly includes a pair of blade carriers 55 similar in construction to the cutter carriers 35 with each having an opening 57 formed in a hub portion 59 with the opening adapted to tit around the bushing so as to pivot the blade carrier on the bushing. The carrier portions 60 to which the slug pullers or blades 61 are attached are offset laterally relative to the hub portions 59 in the manner shown in FIG. 8. Thus, the slug pulling blades are aligned when the carriers 55 are positioned side by side on the bushing. The blade carriers are positioned on the bushing between a headed portion 62 at the end thereof and the end of the front portion 13 of the housing. The slug pulling blades 61 t into the incision formed in the insulation by the cutters 40 and contact the end of the severed portion of insulation. The cutters 40 and slug puller blades 61 come together to cut the insulation and contact the severed portion of insulation in the manner shown in FIG. 11.

The blades 61 may be of any conventional design and may be attached to the blade carriers in any conventional manner. For example, the blades may be formed with notches 62 of various sizes so that the stripper may be used for a variety of wires. The blades may be attached to the carriers by brazing, threaded fasteners or pins. The blades may also be formed as integral parts of the carriers. A torsion spring 63 is connected at its opposite ends to the blade carriers and lits around the bushing 25 to urge the blades apart. End portions 64 of the blade carriers are located on the opposite side of the hub portions 59 from the blade support portions 60. These end portions are offset laterally from the hub portions and align with the blade support portions. Laterally extending tabs 65 are attached to the carrier end portions 64 and support adjusting screws 66 for a purpose to be described later. A pin and socket (not shown) similar to pin 48 and socket 49 may be formed on the carriers 55.

A smaller bore 67 (FIG. 2) extends through the front housing portion 13 generally paralleling the bore 21. A similar bore k69 is formed in the rear housing portion 15 in alignment with the bore 67. An actuating rod 71 extends through the bore 67 and into the bore 69. The forward end of the rod 71, which extends outwardly of the front housing portion 13, is tapered at 73. The opposite end of this rod is connected to the rear housing portion 15 by means of a pin 75 which extends radially through the rod. The bores 67 and 69 are enlarged at 77 and 79 respectively to receive a coiled compression spring 81 which tits around the rod 71 and bears against the front and rear portions of the housing 11. The tapered end 73 of the rod 71 contacts the end portions 44 of the cutter carriers 35 to hold the end portions slightly apart, as shown in FIG. 5, and to pivot the cutters together upon movement of the carriers relative to the rod. A tab 82 extends from the cover 45 of the cutter assembly and ts between and contacts the cutter carriers when the blades are urged apart by the spring 43. This keeps the carriers erect on the shaft 28 if the tapered end 73 of the rod 71 is removed from contact with the end portions 44 of the cutter carriers.

A detent means 85, shown in FIGS. 1, 4 and 7, is attached t the front housing portion 13 to prevent movement of the shaft 28 relative to this portion of the housing during initial movement of the handles 17 and 19 towards each other. The detent means includes a ball 87 retained in a socket by a leaf spring 89 which is mounted on the front housing portion 13. The ball fits through an opening 91 in the front housing portion 13 and into a socket 93 formed in the shaft 28.

A wire cutting assembly 97, shown in an enlarged view in FIG. 7, is mounted on the front housing portion 13 and is spaced from the slug pulling assembly 53 a predetermined distance equal to the desired length of the stripped portions of the wires. This assembly includes a pair of blades 99 which are pivotally mounted at 101 on a support 103 attached to the top of the front housing portion 13. A torsion spring 104 is attached to the blades and urges them apart. An elongated actuator rod 105 (FIG. 3) having a tapered point 107 is aixed to the rear housing portion 15 and is adapted to slide through a slot 109 in the support 103. The tapered point engages the portions 111 of the blades 99 that extend beyond the pivotal mounting 101 towards the front housing portion 13. The engagement of the tapered point 109` with the portions 111 of the blades spreads these portions and brings the blades 99 together to cut the wire. The actuator rod may be adjusted relative to the rear housing portion 15 by means of screws 113 and slots 115 (FIG. l) to vary the amount of movement of the front and rear housing portions towards each other required before the blades completely close.

A wire positioner 121, shown enlarged in FIGS. 9 and 10, tits into slots 123 formed in the headed portion 62 of the bushing 2S (FIG. 8) to align the wire to be stripped with the correct sets of notches in the cutter and slug puller assemblies. The wire positioner is made from a flat piece of metal having an arcuate shaped end 125 defininga central depression or groove |127 which aligns the wire with the selected set of notches. The other end of the positioner is bifurcated forming spaced legs 129 which t into the slots in the bushing 25. To retain the positioning member relative to the bushing, the legs 129 are corrugated in the manner shown in FIG. l0. The corrugated portions contact the sides of the s-lots in the bushing to restrain accidental or inadvertent movement of the positioner.

Although the stripper has been shown and described with cutters attached to the front assembly 33 and slug pullers attached to the rear assembly 53, it should be understood that this may be reversed. In other words, the cutters may be attached to the slug puller carrier or the slug pullers may be attached to the cutter carriers.

The use, operation and function of the invention are as follows:

The Irst step in using this invention is to place the Wire positioner 121 is alignment with a selected set of notches 41 and 62 in the slug pullers and cutters. As is conventional in such strippers, the notches at the outer or upper portion of the cutters and slug pullers are generally smaller than those closer to the inside or base of the cutters and slug pullers. With the wire positioner in its selected location and the stripper in the condition shown in FIG. l with the handles 17 and 19 spaced the maximum distance apart under the urging of the coil spring y81, a length of wire to be stripped (not shown) is placed between the slug pulling blades 61 and cutters 40 extending to and beyond the blades 99 of the wire cutting assembly 97. The stripped length of Wire .may be less than the spacing between the slug puller assembly 53 and the wire cutting blade assembly 9:7. In such instances, the cutting assembly 97 is not used.

With the wire to be stripped thus properly positioned, the front and rear handles 17 and 19 are gripped and pulled towards each other. During initial movement of the handles towards each other, the Iwire cutter assembly 97 on the front housing portion 13 will move relative to the tapered portion 107 of the rod 105 thereby operating the wire cutters 99. At the same time, the shaft 28 will move with the front portion :13 of the housing because the detent means prevents it from moving relative thereto. Thus, the cutter assembly 33 and slug puller assembly 53 will move with the shaft 28 relative to the actuator rod 71 which remains stationary relative to the rear handle 19 and housing 15. As the slug puller and cutter assemblies move relative to the actuating rod 71, the tapered portion 73 of the rod will engage the end portions 44 of the cutter carriers 35 to close the cutters 40 against the wire. At the same time, the tapered portion 73 of the rod 71 will engage the adjusting screws 66 mounted on the insulation slug pulling blade carriers 55 to pivot the blades 61 together to contact the end of the severed portion of insulation on the wire. The slug pulling blades will be fully closed when the nylon screws 66 are in contact with the rod 71 beyond the tapered portion thereof. The cutting of the wire, cutting of the insulation, and pulling of the severed portion of insulation will occur before the slug pulling and cutter assemblies are moved linearly relative to each other.

Continued movement of the handles 17 and 19 towards each other will carry the pin 29 on the shaft 28 into engagement 'with the end of the slot 31 in the rear partion 19 of the housing to thereby diseng-age the detent means 85 from the shaft, allowing the front housing 13 to move relative to the shaft. As this occurs, the slug pulling assembly '53 which is mounted on the bushing 25, which in turn is pinned to the front portion 13 of the housing, will move away from the cutter assembly 33 which is aflixed to the shaft 28. Therefore, the slug pulling assembly will pull the severed portion of insulation off the end of the wire. When the handles reach the fully operative position shown in FIG. 4, the severed slug of insulation lwill be completely or almost completely removed from the wire.

Upon release of the handles, the spring 81, which has been compressed during the stripping operation, will return the front housing portion 13 to the position shown in FIG. l. Upon initial release of the handles, the shaft 28 will move away from the rear housing 15 along with the front housing l13 due to the frictional engagement between the detent ball 87 and the shaft. The cutter assembly 33 and slug puller assembly 53 will maintain their positions relative to each other and will move relative to rod 71 releasing the cutters. The relative movement of the shaft `28 and the rear housing portion 15 will continue until the pin 29 contacts the end of slot 31. Then the front housing and slug puller assembly will move relative to the shaft 28 and rod 71 until the cutter and slug puller assemblies come together. At approximately this point, the slug pullers will open due to the screws 66 engaging the tapered portions of the rod 71.

I claim:

1. A Wire stripper including:

a pair of pivotally mounted insulation cutting members,

a pair of pivotally mounted insulation slug pulling members,

means biasing said members to open positions,

means for moving said members to closed wire stripping positions including a rod, 'with said rod and said members being movable axially relative to one another,

said rod having portions positioned to contact said members with relative axial movement of said rod and said members pivoting said members to closed wire stripping positions, and

means for providing relative axial movement between said insulation cutting and slug pulling members after they are closed to move the severed insulation relative to the wire.

2. The structure of claim 1 further characterized in that said rod has a tapered end portion positioned for contact with said slug pulling members and insulation cutting members.

3. The structure of claim 1 further characterized in that said means for causing relative axial movement between said cutting members and said slug pulling members includes a shaft, said member being pivoted about the axis of said shaft.

4. The structure of claim 3y further characterized in that said cutting members are attached to said shaft for axial movement therewith.

5. The structure of claim 3 further characterized in that said shaft is movable axially relative to said slug pulling members.

6. The structure of claim 3 further characterized in that said shaft is parallel to the axially movable rod.

7. The structure of claim 1 further characterized in that the means for causing relative axial movement between said cutting members and slug pulling members includes a shaft and handle means for bringing about relative axial movement between said rod, said shaft and said cutting and slug pulling members.

8. The structure of claim 7 further characterized in that said handle means is positioned relative to said rod and saidshaft to cause axial movement of said rod relative to said slug pulling and cutting members prior to causing axial movement of said shaft relative to either one of said members.

9. The structure of claim 8 further characterized in that said handle means includes a pair of spaced hand gripping members, and yielding means biasing said hand gripping members to a normally open position.

10. The structure of claim 9 further characterized by and including a movable housing portion fixed to one of said hand gripping members, said rod and said shaft extending through said movable housing portion.

11. The structure of claim 10 further characterized by and including a bore in said movable housing portion, said shaft extending through said bore, and means for preventing relative movement between said shaft and movable housing portion until movement of said movable portion has moved said shaft relative to said rod.

12. The structure of claim 11 further characterized in that the means for preventing relative movement between the shaft and the movable housing portion includes detent means comprising a member yieldingly urged into locking contact with said shaft.

13 The structure of claim 12 further characterized in that said detent means includes a ball yieldingly urged into a socket in said shaft.

14. The structure of claim 1 further characterized by and including manual means for axially moving said rod and said members relative to one another and for causing operation of the means for providing relative axial movement between the cutting members and slug pulling members after they have been moved to their closed positions, and means for cutting a wire to be stripped, said cutting means being operable by said manual means.

References Cited UNITED STATES PATENTS 3,002,408 lO/l96l Schwalm et al. 819.5l 3,154,980 11/1964 Hayden et al. 81-951 ROBERT C. RIORDON, Primary Examiner R. V. PARKER, IR., Assistant Examiner 

